I have light brown splotchy spots under my left breast.
I'm 13. Female.
When I first noticed it (about a month ago) it was one spot about the size of a dime.
now it is several spots in an area about the size of my palm.
I don't tan topless, so I don't think it's sub damage.
It may be nothing, but I'm a bit worried because breast cancer runs through the family.
What else could it be?
What should I do?

Ok...I can't see the spots so it's difficult. You really should ask mom to look at them. Are the spots flat like freckles, or raised like a rash? Are they truly light brown or slightly red? Sometimes in the hot weather months and we sweat under the breasts, we can get a yeast infection under them...but that is usually reddish, and sometimes a little itchy. I have found that if you go to the section of the pharmacy that sells feminine products, and select a salve that is normally used for a vaginal yeast infection and apply it under the breast, it will cure the yeast infection there as well.

Otherwise, I don't know what to tell you. Breast cancer isn't usually something that is on the skin. It may be a lump in the breast that wouldn't otherwise be there. If ever you feel a lump that shouldn't be there, get to your gynecologist really soon.

Please, your mother is your friend (hopefully), even if you think she's a bit "old fashioned". She wants you to be healthy and happy too. If the salve doesn't work, try talking to her.